The non-native Areca triandra palm is a potential threat to the Southwestern rainforests of Sri Lanka

The palm family is a major source of invasive plants because of their long
history of introductions outside their native range in tropical and
subtropical regions for their use as food and ornamentals. Areca triandra
was introduced to Sri Lanka in 1867 through the Royal Botanic Gardens,
Peradeniya and has been grown as an ornamental for over a century. To
assess its potential invasiveness, we applied an invasiveness assessment
protocol. Population and reproductive characteristics were studied in
Meethirigala and Yagirala Forest Reserves. In each location, stems
> 1 m in height were sampled and crown cover was assessed in three
plots of 400 m2 (20 × 20 m) and the ground layer < 1 m height
sampled through four 1 x 1 m quadrats within each 400 m2 (total of 24
quadrats). Areca triandra accounted for 56 - 66% of stems > 1 m
height, 52 - 76% crown cover, and 64 - 77% of saplings and seedlings in
the ground layer < 1 m height. Clump formation was high with 30 -
51% having 2 - 7 stems, compared to single stems of 12 - 26%. Fruit
production was prolific, 140 - 250 fruits per infructescence, and each
clump of multiple stems producing 1 - 3 infructescences. This resulted in
a total of 250 - 440 fruits per clump, translating up to 8000 fruits per
20 m × 20 m plot; bright red, (one-seeded) fleshy drupes attracted avian
and mammalian frugivores, aiding seed dispersal. This species was
colonized along the disturbed forest edges where it can compete with
native species, exposing vulnerability of highly fragmented rainforests.
This study shows that the species is naturalized in the southwest humid
lowlands and can be considered a potential invasive emphasizing the need
for urgent actions to manage this species.